Question

Would you expect C₆₀ to form a stronger complex with IrCl(CO)[P(CH₃)₃]₂ or IrCl(CO)[P(C₆H₅)₃]₂? Which of the two alkenes, C₂H₄ or C₂FH₃ , more closely resembles C₆₀ in terms of its coordination properties?

Answer 1

The reactivity of Vaska’s complex can be altered by modifying the ligands. Alkylphosphines produce Vaska-type complexes are more prone to oxidative-addition than complexes with aryl phosphine ligands

The binding constant for oxidative addition to Ir(CO)- Cl(PMe3)2 is about much larger than it is for Ir(CO)Cl(PPh3)2.

Hence C60 would form a stronger complex with IrCl(CO)[P(CH3)3]2 than IrCl(CO)[P(C6H5)3]2.

The C60 i.e. fulerene ligand resembles most commonly to electron-deficient alkenes such as ethylene.